This invention relates generally to agricultural machines and, in particular, to a swivel hitch for connecting an implement to a tractor.
U.S. Pat. No. 4,738,461 to Stephenson et al discloses a swivel hitch including an upper gearbox coupled to an input shaft on an implement and a lower gearbox connected to a power-take-off shaft on a tractor. In order to achieve the desired maneuverability of the implement during normal operation, the lower gearbox rotates relative to the upper gearbox about a vertical axis when the tractor makes turns. The upper gearbox is rigidly mounted on a tongue extending forwardly from the implement and has an input shaft coupled to an output shaft on the lower gearbox by a coupling device. The lower gearbox is rigidly bolted to a bracket carried by a hitch adaptor that is attached to the tractor. If there is any misalignment between the lower gearbox output shaft and the upper gearbox input shaft, it will be difficult to couple these shafts together.